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Abstract Zeolitic nanosheets possess great potential in catalysis due to their enhanced transport property and accessibility toward bulky molecules compared to conventional micron‐ meter scale crystals. However, the generation of Beta zeolite nanosheets, which are crucial for industrial catalysis, is still challenging for its intergrowth nature. In this work, aluminosilicate Beta nanosheets of ca. 16 nm thick with house‐of‐cards architecture are generated using a special polycationic organic structure directing agent (OSDA), ‐N + (CH 3) 2 ‐C 5 H 10 ‐N + (CH 3) 2 ‐C 6 H 12 ‐ n Br − 2n, in greener hydroxide media. Transmission electron microscopy and electron tomography reconstruction revealed that the nanosheets are composed of unprecedented intergrowth of polymorphs B and polymorph C (i. e. , BEC topology), possessing only straight micropore channels. 2D 29 Si 1 H and 27 Al 1 H heteronuclear correlation NMR spectra reveal that the framework Al atoms are mainly situated close to the ammonium moieties of the OSDA inside straight channels, owing to a strong OSDA‐framework attraction. The selectivities of ethylene, propylene and catalyst lifetime have been promoted in n ‐heptane cracking, due to stronger acidity and enhanced diffusion property. Moreover, the architecture is robust toward deep dealumination and Ti‐ modification, allowing it to be a superior catalyst in cyclohexene epoxidation. The polycation OSDA design concept and the recipe for Beta nanosheets may find broader applications in catalysis.
Qie et al. (Sun,) studied this question.